New research published in Science Advances (October 2026) confirms that the White Sands footprints date to 23.5- 21.7 thousand years ago (during the Last Glacial Maximum) and shows that the people who made them experienced rapid, generation- scale environmental changes.
Expanded excavations at White Sands National Park (New Mexico) uncovered additional stratigraphic horizons within situ human footprints, megafaunal trackways (mammoths, giant sloths, dire wolves), and linear features interpreted as travois marks.
Researchers refined the chronology using innovative methods to isolate large quantities of conifer pollen grains (up to 75,000 per sample) for radiocarbon dating, combined with ages from aquatic seeds, at the USGS Radiocarbon Laboratory. This reaffirmed and sharpened the earlier dating of the site.
High- resolution paleoclimate reconstruction (at roughly 50- year intervals, comparable to a human generation) used pollen assemblages, biomarkers, leaf- wax hydrogen isotopes, and stratigraphy.
Key findings include:
- A complete landscape turnover from conifer forest to sagebrush and oak steppe.
- Recession of the large pluvial Lake Otero (which once covered much of the modern park area) into a wet playa and lake- margin setting, with water levels fluctuating over ~1,500 years before further shrinkage.
- Centennial- scale swings in water availability, including a severe aridification episode coincident with Dansgaard- Oeschger event 2 (~23.2 ka), an abrupt Northern Hemisphere warming recorded in Greenland ice cores. Local aridity changes tracked these global shifts.
- Average temperatures in the Southwest around ~50°F (cooler than today’s ~60°F annual mean in the area), with vegetation shifts (e.g., pine forest to pinyon-juniper) occurring within about 100 years.
The earliest track horizons align with the lake drawdown during D- O 2, which exposed a mosaic of wet and dry ground along the former shoreline that humans and megafauna then traversed for nearly two millennia.
University of Arizona co- author Jessica Tierney (Department of Geosciences) noted the sediments’ unique high temporal resolution and the rarity of combining detailed paleoclimate data with archaeology in the same place; the footprints remain remarkably well preserved in gypsum mud.
USGS co- lead author Kathleen Springer highlighted that early humans were real- time witnesses to changes discernible within a human lifetime. Anthropologist Ed Jolie (University of Arizona) connected the findings to the deep Indigenous past of the Americas and support for Native oral traditions.
This builds on prior work dating the footprints and strengthens evidence for human presence in North America during the Last Glacial Maximum, south of the continental ice sheets. The study was a collaboration involving the University of Arizona, USGS, and other partners.
Humans experienced abrupt environmental changes at White Sands during the Last Glacial Maximum | Science Advances
Dansgaard- Oeschger event 2 (D- O 2 or DO- 2) was one of a series of abrupt climate fluctuations that occurred repeatedly during the last glacial period (roughly 115,000- 11,700 years ago).
What are Dansgaard-Oeschger events?
Named after Danish paleoclimatologist Willi Dansgaard and Swiss physicist Hans Oeschger, these events are best recorded in Greenland ice cores.
Each typically follows a characteristic “sawtooth” pattern:
- A very rapid warming phase (often 5- 15 °C / 9- 27 °F in Greenland air temperatures) occurring over just a few years to a few decades.
- A subsequent gradual cooling phase lasting centuries to a few millennia.
- Often ending with a sharper return to cold (stadial) conditions.
About 25 such events are recognized in the last glacial cycle.
They show an average spacing of roughly 1,470 years, though the timing is not perfectly regular. The warm phases are called Greenland Interstadials (GI); the cold phases are Greenland Stadials (GS).
The leading explanation involves changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC), the large- scale ocean current system that transports heat northward in the Atlantic.
Weaker AMOC → colder North Atlantic and Greenland (stadial); stronger AMOC → rapid warming (interstadial). Sea- ice extent in the North Atlantic is thought to play a major amplifying role. Exact triggers remain under active research and may involve interactions among ocean circulation, ice sheets, atmosphere, and possibly external forcings.
Timing and characteristics of D- O 2 specifically
D- O 2 began approximately 23.3- 23.4 thousand years ago (around 23,340 years before 2000 CE in the NGRIP ice- core chronology). It occurred near the peak of the Last Glacial Maximum, when global ice sheets were near their maximum extent.
In Greenland, it produced the classic rapid warming followed by gradual cooling. Its global teleconnections varied by region.
Relevance to White Sands and the American Southwest
In the recent White Sands National Park studies, D-O 2 is linked to a marked aridification episode around 23.2 ka. The abrupt Northern Hemisphere warming is interpreted to have increased evaporation and reduced effective moisture in the Southwest, causing pluvial Lake Otero to shrink rapidly. This exposed a mosaic of wet and dry lake-margin surfaces that humans and megafauna then walked across, preserving the famous footprints. Local pollen, biomarker, and isotopic records show centennial-scale swings in aridity and a vegetation shift coincident with this event.
In short, D- O 2 was a short- lived but intense pulse of climate instability superimposed on the already cold, ice- age world, strong enough to be felt far from Greenland, including in the landscapes of Ice Age New Mexico.
Humans experienced abrupt environmental changes at White Sands during the Last Glacial Maximum
Abstract (key points)
Expanded excavations at White Sands National Park (Locality 2) revealed 20 stratigraphic horizons containing in situ human footprints, megafaunal trackways, and linear features interpreted as travois marks.
Advances in radiocarbon dating of conifer pollen, combined with ages from aquatic seeds, refine the chronology of the footprint- bearing sequence to 23.5- 21.7 thousand years ago (ka).
Biomarker, pollen, and stratigraphic evidence show a complete environmental overturning from a perennial lake to a playa. A large aridification episode coincided with Dansgaard- Oeschger event 2 at ~23.2 ka, which shrank pluvial Lake Otero and allowed people (and megafauna) to traverse the former shoreline area for nearly two millennia.
This provides a well- dated, high- resolution paleoclimate record demonstrating that humans in North America experienced marked environmental changes during the Last Glacial Maximum.
Main findings (from available coverage and related materials)
- Chronology: Confirms and refines earlier dating of the White Sands footprints to the height of the Last Glacial Maximum. The sequence spans almost 2,000 years of repeated human presence.
- Environmental reconstruction (high temporal resolution, ~50- year intervals):
- Began with a large Lake Otero and surrounding conifer forests; temperatures ~4- 6 °C cooler than today.
- Progressive warming and drying from ~23.6 ka onward: conifers declined and were replaced by oak and sagebrush steppe.
- Sharp centennial- scale swings in hydroclimate, including a severe drought ~23.2 ka (linked to D- O 2) that increased lake salinity and expanded drought- tolerant vegetation.
- Lake levels fluctuated and overall receded into a wet playa and lake- margin setting.
- Earliest footprint horizons align with the D- O 2 transition and lake drawdown that exposed suitable muddy surfaces. People continued to visit as conditions changed.
- Authors (including USGS researchers Kathleen Springer and Jeff Pigati, and University of Arizona’s Jessica Tierney) note the rarity of such a high- resolution multiproxy record tied directly to human and megafaunal activity in the same place.
A USGS data release accompanying the paper is available (DOI: 10.5066/P13W7HTM).
The full text on Science.org is typically behind a paywall or institutional access; secondary summaries (e.g., University of Arizona, EurekAlert, The Conversation) and the abstract provide the core results.
Related earlier papers confirmed the age of the footprints using multiple independent dating methods (seeds, pollen, OSL).
Journal: Science Advances
Provided: University of Arizona
Authors: Springer, K. B., Pigati, J. S., Tierney, J. E., et al. (2026)
White Sands Footprints and Ice Age Environmental Shifts / X
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